Shut down the laptop completely
Disconnect the power adapter
Remove all external devices
If the battery is removable, remove it
Press and hold the power button for 15 to 30 seconds
Reconnect the battery if removed
Reconnect the power adapter
Turn on the laptop
If needed, press and hold the power button for 10 to 15 seconds to force shutdown, then power it on again
If the laptop has a pinhole reset, use it according to the Dell model instructions